Portable desk



FIG. 1 is a left front perspective view of a portable desk showing my new design;

FIG. 2 is a left rear perspective view thereof, the right side being substantially similar to the left side;

FIG. 3 is a bottom plan view thereof; and

FIG. 4 is a left front perspective view similar to FIG. 1 with the compartments in the open position. 

The ornamental design for a portable desk, substantially as shown and described. 